Z Axis noise level

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terrymcc
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Z Axis noise level

Post by terrymcc »

I continue to work through the startup of my Mill Turn conversion. Acorn/CNC12 rocks!

My Z axis is significantly louder than the X and Y. The X and Y are direct drive ball screws. The machine is like a bridge mill in the milling mode so the Z axis is mechanically more complex than X and Y. There are 2 ball screws (one at each end of the bridge) driven by a 1" timing belt. The original machine was steppers and at 40ipm on X and Y and 20ipm on Z, I would intermittently loose skips. The conversion is 8.5NM hybrid servos. I haven't pushed them to the point of faulting, but at 200ipm X and Y and 80ipm Z it has no issue. That seems fast enough for my application.

In any case, the Z works fine with no apparent backlash. It's just loud. I can't really tell if it is drive noise or mechanical. I assume a lot of it is mechanical. I didn't see how to attach a video to this post, so below is a short youtube of the axis moves. The popping noise during slow Z moves is the timing belt working its way across the timing pulley slightly. Everything is lubricated....

What do you think about the noise level and potential source? Is it normal for that kind of drive?

Thanks

martyscncgarage
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Re: Z Axis noise level

Post by martyscncgarage »

Cool you are making progress. I do seem to hear a rattle, but doesn't seem like Z axis drive issues. You have ALOT going on on Z axis, weight, round linear rails and the screws. Since you didn't post a report, I assume you left the accel/decel at .5sec in the Axis config menu?

I'm not surprised at the noise. Is there a way to time the two Z axis screws? (Assuming there are two ballscrews on either end)
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terrymcc
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Re: Z Axis noise level

Post by terrymcc »

Thanks for the feedback Marty. Yes, left Accel at .5sec. I think I will slightly loosen the timing belt to see if popping goes away. It has been so long since the original machine ran, I can't remember if it was noisy. I do know it would never move like that!

You can clock the ball nuts 1/4 turn for timing/tram. That was a bit much so I used some shim washers to get the tram correct. Now that all the milling functions are up and going, I am going to move the applicable parameters into the lathe version of cnc12 and get it checked out.

When we send in a Report, how do you look at it? are there some specific files you open to look at settings, or do you just open CNC12 with the report contents?

I have been pretty thorough in preparing schematics and documenting the build. I thought I might do some videos and then put it all on line in case it would be beneficial to someone else. Is success stories the proper place to do that?
martyscncgarage
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Re: Z Axis noise level

Post by martyscncgarage »

terrymcc wrote: Wed Jan 13, 2021 5:41 pm Thanks for the feedback Marty. Yes, left Accel at .5sec. I think I will slightly loosen the timing belt to see if popping goes away. It has been so long since the original machine ran, I can't remember if it was noisy. I do know it would never move like that!

You can clock the ball nuts 1/4 turn for timing/tram. That was a bit much so I used some shim washers to get the tram correct. Now that all the milling functions are up and going, I am going to move the applicable parameters into the lathe version of cnc12 and get it checked out.

When we send in a Report, how do you look at it? are there some specific files you open to look at settings, or do you just open CNC12 with the report contents?

I have been pretty thorough in preparing schematics and documenting the build. I thought I might do some videos and then put it all on line in case it would be beneficial to someone else. Is success stories the proper place to do that?
You probably did, but I would make sure those nuts/screws are calibrated correctly and not binding on Z axis. I hear tinging like metal rattling.
If Z never had high speed rapids like you are doing now, you may have found the reason. Try and step it back to what the machine had and listen.
Everyone is infatuated with how fast the machine can rapid. I would care more about how reliably the machine can cut first. Why shake the machine apart just to see how fast it can go? ;)
Yes, please, do document your setup. I think you are the first one that I know of that did one of these machines! That's cool!
Marty
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terrymcc
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Re: Z Axis noise level

Post by terrymcc »

How would time them. Just by listening?
martyscncgarage
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Re: Z Axis noise level

Post by martyscncgarage »

terrymcc wrote: Wed Jan 13, 2021 6:02 pm How would time them. Just by listening?
I don't know anything about those machines. If it has two ball screws on the Z axis, it would seem to me they have to be timed to raise both sides exactly the same height at the same time. I would imagine binding would occur otherwise and likely some inaccuracy in the Z depth of travel?
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tblough
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Re: Z Axis noise level

Post by tblough »

I would expect they are "timed" by tramming the spindle to the table. Rasie or lower one side until the spindle is square with the table.
Cheers,

Tom
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terrymcc
Posts: 61
Joined: Fri Nov 27, 2020 11:34 pm
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CNC12: Yes
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CNC Control System Serial Number: waiting on delivery
Location: Pattison, TX
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Re: Z Axis noise level

Post by terrymcc »

tblough wrote: Wed Jan 13, 2021 6:57 pm I would expect they are "timed" by tramming the spindle to the table. Rasie or lower one side until the spindle is square with the table.
That is what I had done. I also measured from the bridge to the lathe bed and that is the same. It is pretty noisy though
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